From 8372838271933fd0a8b363d01e8f20bc43a4ead8 Mon Sep 17 00:00:00 2001
From: Fabian Stemmler <stemmler@in.tum.de>
Date: Fri, 21 Jun 2019 15:02:41 +0200
Subject: [PATCH] Quickfix for Wire.fuse(...)

The fusion of Wires caused an exception upon updating Wire values, if
one of the fused Wires had no inputs, other than the Wire it was fused
with.

The Connector Component still has this issue.
---
 .../mograsim/logic/core/tests/ComponentTest.java  | 15 +++++++++++++--
 .../src/net/mograsim/logic/core/wires/Wire.java   |  7 +++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/net.mograsim.logic.core/src/net/mograsim/logic/core/tests/ComponentTest.java b/net.mograsim.logic.core/src/net/mograsim/logic/core/tests/ComponentTest.java
index 0505b4ce..cc170cb7 100644
--- a/net.mograsim.logic.core/src/net/mograsim/logic/core/tests/ComponentTest.java
+++ b/net.mograsim.logic.core/src/net/mograsim/logic/core/tests/ComponentTest.java
@@ -88,7 +88,7 @@ class ComponentTest
 	}
 
 	@Test
-	void fusionTest()
+	void fusionTest1()
 	{
 		t.reset();
 		Wire a = new Wire(t, 3, 1), b = new Wire(t, 2, 1), c = new Wire(t, 3, 1), out = new Wire(t, 8, 1);
@@ -117,6 +117,17 @@ class ComponentTest
 		assertBitArrayEquals(rC.getValues(), Bit.ZERO, Bit.ONE, Bit.ZERO);
 	}
 
+	@Test
+	void fusionTest2()
+	{
+		t.reset();
+		Wire a = new Wire(t, 3, 1), b = new Wire(t, 3, 1);
+		Wire.fuse(a, b);
+		a.createReadWriteEnd().feedSignals(Bit.ONE, Bit.U, Bit.Z);
+		t.executeAll();
+		assertBitArrayEquals(b.getValues(), Bit.ONE, Bit.U, Bit.Z);
+	}
+
 	@Test
 	void triStateBufferTest()
 	{
@@ -430,7 +441,7 @@ class ComponentTest
 
 		TestBitDisplay test = new TestBitDisplay(t, c.createReadOnlyEnd());
 		TestBitDisplay test2 = new TestBitDisplay(t, a.createReadOnlyEnd());
-		LongConsumer print = time -> System.out.format("Time %2d\n   a: %s\n   b: %s\n   c: %s\n", time, a, b, c);
+		LongConsumer print = time -> System.out.format("Time %2d\n a: %s\n b: %s\n c: %s\n", time, a, b, c);
 
 		cI.feedSignals(Bit.ONE);
 		test.assertAfterSimulationIs(print, Bit.ONE);
diff --git a/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java b/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java
index 20bcad1e..13e83592 100644
--- a/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java
+++ b/net.mograsim.logic.core/src/net/mograsim/logic/core/wires/Wire.java
@@ -567,8 +567,11 @@ public class Wire
 		@Override
 		public void update(LogicObservable initiator)
 		{
-			ReadWriteEnd read = (ReadWriteEnd) initiator;
-			target.setValues(fromTarget, read.wireValuesExcludingMe().subVector(fromSource, fromSource + length));
+			ReadWriteEnd source = (ReadWriteEnd) initiator;
+			BitVector targetInput = (source.getWire().inputs.size() > 1)
+					? source.wireValuesExcludingMe().subVector(fromSource, fromSource + length)
+					: BitVector.of(Bit.Z, length);
+			target.setValues(fromTarget, targetInput);
 		}
 	}
 }
\ No newline at end of file
-- 
2.17.1